Characterization of Archaea membrane lipids in radioactive springs using shotgun lipidomics.

Lipids from microorganisms, and especially lipids from Archaea, are used as taxonomic markers. Unfortunately, knowledge is very limited due to the uncultivability of most Archaea, which greatly reduces the importance of the diversity of lipids and their ecological role. One possible solution is to use lipidomic analysis.

PLGA-based nanocarriers for combined delivery of colchicine and purpurin 18 in cancer therapy: Multimodal approach employing cancer cell spheroids.

Improving the anticancer efficacy of chemotherapeutic drugs and photosensitizers requires innovative multifunctional nanoplatforms. This study introduces a chemo- and phototherapeutic drug delivery system (DDS) based on poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs), both PEGylated and non-PEGylated, with a mean size of 200 ± 75 nm. Colchicine (Colch) and purpurin18 (P18) were co-encapsulated into these NPs, and their in vitro drug release profiles were investigated.

Comprehensive UHPLC-MS screening methods for the analysis of triazolopyrazine precursor and its genotoxic nitroso-derivative in sitagliptin pharmaceutical formulation.

A case study on Sitagliptin drug products and Sitagliptin/Metformin drug products concerning contamination with N-nitrosamines was performed using two newly developed analytical methods for determination of N-nitroso-triazolopyrazine (NTTP; 7-nitroso-3-(trifluoromethyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine) and its precursor triazolopyrazine (3-(trifluoromethyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine). The method for determination of triazolopyrazine was previously unpublished, the method for determination of NTTP was published only for analysis of active pharmaceutical ingredient Sitagliptin and not the drug forms. Solving the N-nitrosamine contamination is requested by regulatory authorities all over the world and thus is vital for all pharmaceutical companies.

Gold nanoshells with magnetic cores and a urea-based receptor for SERS sensing of fluoride anions: experimental and computational study.

The study demonstrates that a combination of plasmonic nanostructures and artificial receptors can be applied for sensing small molecular species. Gold nanoshells containing magnetic cores are used as the SERS-active substrates, which opens the way for the development of multimodal contrast agents with applicability extended to sensing or for the separation of analytes by magnetic solid-phase extraction. Disubstituted ureas forming hydrogen-bonded complexes with certain anions can be employed as molecular sensors.

Analytical Quality by Design-Compliant Development of a Cyclodextrin-Modified Micellar ElectroKinetic Chromatography Method for the Determination of Trimecaine and Its Impurities.

In 2022, the International Council for Harmonisation released draft guidelines Q2(R2) and Q14, intending to specify the development and validation activities that should be carried out during the lifespan of an analytical technique addressed to assess the quality of medicinal products. In the present study, these recommendations were implemented in Capillary Electrophoresis method development for the quality control of a drug product containing trimecaine, by applying Analytical Quality by Design. According to the Analytical Target Profile, the procedure should be able to simultaneously quantify trimecaine and its four impurities, with specified analytical performances.

Azobisisobutyronitrile loaded on mesoporous silica particles: A new stressor for solid-state oxidative forced degradation studies.

A new approach for testing drug sensitivity to autooxidative degradation in the solid state is demonstrated in this work. A novel solid-state form of stressing agent for autooxidation has been proposed, based on azobisisobutyronitrile loaded into mesoporous silica carrier particles. The new solid-state form of the stressing agent was applied in degradation studies of two active pharmaceutical ingredients: bisoprolol and abiraterone acetate.

Multimodal Contrast Agent Enabling pH Sensing Based on Organically Functionalized Gold Nanoshells with Mn-Zn Ferrite Cores.

Highly complex nanoparticles combining multimodal imaging with the sensing of physical properties in biological systems can considerably enhance biomedical research, but reports demonstrating the performance of a single nanosized probe in several imaging modalities and its sensing potential at the same time are rather scarce. Gold nanoshells with magnetic cores and complex organic functionalization may offer an efficient multimodal platform for magnetic resonance imaging (MRI), photoacoustic imaging (PAI), and fluorescence techniques combined with pH sensing by means of surface-enhanced Raman spectroscopy (SERS). In the present study, the synthesis of gold nanoshells with Mn-Zn ferrite cores is described, and their structure, composition, and fundamental properties are analyzed by powder X-ray diffraction, X-ray fluorescence spectroscopy, transmission electron microscopy, magnetic measurements, and UV-Vis spectroscopy.

Pentamethinium Salts Nanocomposite for Electrochemical Detection of Heparin.

This study presents a simple route to heparin detection and develops a voltammetric approach using supramolecular principles and nanomaterials. Nanocomposites, including gold nanoparticles (AuNPs) and γ-substituted pentamethinium salts (PMS) deposited on a glass carbon (GC) electrode surface (GC/AuNPs/PMS) and covered by a plasticized poly(vinyl chloride) (PVC) membrane, are proposed for heparin detection. The conductivity of the nonconducting PVC-plasticized membrane is guaranteed by AuNPs, and the selectivity is provided by the interaction between γ-substituted PMS and anionic analytes.

Insight into the formation of N-nitrosodimethylamine in metformin products.

An effective analytical method for the quantification of N-nitrosodimethylamine (NDMA) using a liquid chromatography coupled with tandem mass spectrometry was developed and applied to a process optimization study of the production of metformin film coated tablets in order to identify the key factors behind the NDMA formation in metformin products. The method uses a linear gradient elution with mobile phases 0.1 % formic acid in water for chromatography and methanol for chromatography and a column Acquity UPLC HSS T3 1.

New multimodal stationary phases prepared by Ugi multicomponent approach.

Eight different stationary phases based on two aminopropyl silicas of different brands suitable for multimodal chromatography applications have been prepared by a four-component Ugi reaction. The intention was to synthesize stationary phases significantly differing in their properties hereby demonstrating flexibility of the Ugi synthetic protocol. Diverse functional groups including a nonpolar long aliphatic chain, phenyl moiety, cholic acid scaffold, phenylboronic and monosaccharide units, charged betaine, and arginine moieties were immobilized on a silica surface.

Enantioseparation and Determination of Mephedrone and Its Metabolites by Capillary Electrophoresis Using Cyclodextrins as Chiral Selectors.

Mephedrone, a psychoactive compound derived from cathinone, is widely used as a designer drug. The determination of mephedrone and its metabolites is important for understanding its possible use in medicine. In this work, a method of capillary electrophoresis for the chiral separation of mephedrone and its metabolites was developed.

Cyclodextrin-Functionalised Nanomaterials for Enantiomeric Recognition.

Cyclodextrins, which are glucose-based cyclic oligosaccharides, are materials that can act inherently as chiral selectors, with many reports of the application of cyclodextrins in enantioseparation. However, many studies have encountered the problem of insufficient enantioselective performance of the chiral selector. One of the main reasons is due to low surface concertation's, whereby interaction between the chiral selector and analyte usually occurs at a surface.

Recent advances in mixed-mode chromatographic stationary phases.

Mixed-mode phases have become very popular in the last decade, and the number of new mixed/multi-mode sorbents is growing fast. Unlike single-mode stationary phases, perfectly suited for the separation of the analytes possessing similar physicochemical properties, for instance reversed-phase chromatography for hydrophobic solutes, mixed-mode sorbents providing multimodal interactions can render better separation selectivity for complex mixtures of solutes differing significantly in their physicochemical characteristics. The most frequent modern mixed-mode stationary phases are di/tri-mode sorbents embracing the following interactions, hydrophobic, electrostatic (coulombic), and hydrophilic.

Influence of substituent position and cavity size of the regioisomers of monocarboxymethyl-α-, β-, and γ-cyclodextrins on the apparent stability constants of their complexes with both enantiomers of Tröger's base.

Enantiomers of Tröger's base were separated by capillary electrophoresis using 2(I) -O-, 3(I) -O-, and 6(I) -O-carboxymethyl-α-, β-, and γ-cyclodextrin and native α-, β-, and γ-cyclodextrin as chiral additives at 0-12 mmol/L for β-cyclodextrin and its derivatives and 0-50 mmol/L for α- and γ-cyclodextrins and their derivatives in a background electrolyte composed of sodium phosphate buffer at 20 mmol/L concentration and pH 2.5. Apparent stability constants of all cyclodextrin-Tröger's base complexes were calculated based on capillary electrophoresis data.

The influence of the substituent position in monocarboxymethyl-γ-cyclodextrins on enantioselectivity in capillary electrophoresis.

Three newly synthesized chiral selectors, namely, 2(I)-O-, 3(I)-O-, and 6(I)-O-carboxymethyl-γ-cyclodextrin, native γ-cyclodextrin, and commercially available carboxymethylated γ-cyclodextrin with degree of substitution of 3-6 were used as additives in a background electrolyte composed of phosphate buffer at 20 mmol/L concentration and pH 2.5. This system was used for the analysis of several biologically significant low-molecular-mass chiral compounds by capillary electrophoresis.

Application of cyclodextrins in chiral capillary electrophoresis.

CE represents a very powerful separation tool in the area of chiral separations. CD-mediated chiral CE is a continuously flourishing technique within the frame of the electromigration methods. In this review, a brief overview of the synthetic procedures leading to modified CDs is provided first.

Nonaqueous capillary electrophoretic enantioseparation of water insoluble Tröger's base derivatives using β-cyclodextrin as chiral selector.

Racemic mixtures of six Tröger's base derivatives were separated by chiral nonaqueous capillary electrophoresis. The separation protocol was optimized first for suitable solvents. Then the applicability of various salts dissolved in organic solvents and their mixtures was evaluated.

Enantioseparation of Tröger's base derivatives by capillary electrophoresis using cyclodextrins as chiral selectors.

The enantioseparation of seven Tröger's base derivatives (TBs) was carried out by capillary electrophoresis using α-, β-, and γ-cyclodextrins as chiral selectors and phosphate at 20 mmol/l concentration, pH 2.5, as background electrolyte. The method was optimized with respect to the concentration of chosen chiral selectors (0-50 mmol/l) and the amount of organic solvent (acetonitrile, 0-25 % (v/v)) in the electrolyte.

The study of enantioselectivity of all regioisomers of mono-carboxymethyl-β-cyclodextrin used as chiral selectors in CE.

This work documents the influence of the position of single carboxymethyl group on the β-cyclodextrin skeleton on the enantioselectivity. These synthesized monosubstituted carboxymethyl cyclodextrin (CD) derivatives, native β-cyclodextrin, and commercially available carboxymethyl-β-cyclodextrin with degree of substitution approximately 3 were used as additives into the BGE consisting of phosphate buffer at 20 mmol/L concentration, pH 2.5, and several biologically significant low-molecular-mass chiral compounds were enantioseparated by CE.

Open-tubular capillary electrochromatography with bare gold nanoparticles-based stationary phase applied to separation of trypsin digested native and glycated proteins.

In this work, open-tubular capillary electrochromatography (OT-CEC) method with bare gold nanoparticles (GNPs)-based stationary phase has been developed and applied for separation of tryptic peptide fragments of native and glycated proteins, bovine serum albumin (BSA), and human transferrin (HTF). The GNPs-based stationary phase was prepared by immobilization of bare GNPs, freshly reduced from tetrachloroaurate(III) ions by citrate reduction, on the sol-gel pretreated inner wall of the fused silica capillary. The separation efficiency, peak capacity, and peptide recovery of this open-tubular capillary column were investigated by varying the experimental parameters such as type and concentration of the buffering constituent and pH of the background electrolyte (BGE), temperature, and separation voltage.

Impact of substituent position in monosubstituted α-cyclodextrins on enantioselectivity in capillary electrophoresis.

In this study, our three recently synthesized regiospecifically monosubstituted carboxymethyl-α-cyclodextrins (CMACDs) were successfully applied for the enantiomeric separation of several biologically important low-molecular weight compounds by capillary electrophoresis. The enantioselectivity of the individual monosubstituted CMACDs added into the background electrolyte (BGE) was studied and compared with the mixture of three monosubstituted CMACDs and with native α-cyclodextrin at pH of the BGE ranging from 2.5 to 11.

Application of bare gold nanoparticles in open-tubular CEC separations of polyaromatic hydrocarbons and peptides.

In this study, bare gold nanoparticles (GNPs) immobilized in the sol-gel-pretreated fused-silica (FS) capillary as a stationary phase for open-tubular capillary electrochromatography (OT-CEC) are for the first time shown to be able to separate both hydrophobic polyaromatic hydrocarbons (PAHs) as well as hydrophilic cationic antimicrobial peptides. Model mixture of four PAHs, naphthalene, fluorene, phenanthrene, and anthracene, was resolved by OT-CEC in the GNP-modified FS capillaries using the hydro-organic background electrolyte (BGE) composed of 20 mmol/L sodium phosphate buffer, pH 7, modified with ACN at 8:2 v/v ratio. On the other hand, three synthetic analogues of an antimicrobial peptide mastoparan PDD-B, basic tetradecapeptides INWKKLGKKILGAL-NH(2), INSLKLGKKILGAL-NH(2) and NWLRLGRRILGAL-NH(2), were separated in aqueous acidic BGEs, pH 2.

Polytetrafluorethylene-Au as a substrate for surface-enhanced Raman spectroscopy.

This study deals with preparation of substrates suitable for surface-enhanced Raman spectroscopy (SERS) applications by sputtering deposition of gold layer on the polytetrafluorethylene (PTFE) foil. Time of sputtering was investigated with respect to the surface properties. The ability of PTFE-Au substrates to enhance Raman signals was investigated by immobilization of biphenyl-4,4'-dithiol (BFD) from the solutions with various concentrations.

Modified porphyrin-brucine conjugated to gold nanoparticles and their application in photodynamic therapy.

Two porphyrin-brucine quaternary ammonium salts were immobilized on gold nanoparticles and their suitability for both in vitro and in vivo photodynamic therapy (PDT) was assayed using the basaloid squamous cell carcinoma PE/CA-PJ34 cell line. In vitro PDT experiments revealed that the gold nanoparticle-bound conjugates were less effective than unbound conjugates in killing cells. However, the same conjugates were more effective in reducing tumor size in vivo, with complete tumor regression observed.